Although CBR, VBR, ABR and UBR traffic classes are designed to support existing and forthcoming services, it is difficult to take full advantage of such flexibility since many data services have unknown traffic characteristics. There is much confusion among users when they are asked to provide UPC parameters for their network services.
The UBR traffic class is specifically designed to provide data services with unknown traffic characteristics. No parameters need to be specified for UBR and it provides the simplest user interface. In fact, UBR is the dominant traffic class in most enterprise networks and in many of the Internet backbone networks built on ATM.
However, new specifications such as IEEE 802.1p/Q specification and IETF Differentiated Services (incorporated by reference herein) are being developed and will likely see widespread deployment over the coming years. Both of these specifications do not assume any knowledge of the traffic characteristic, only that some traffic is “more important”, in some sense, than others. These service specifications do not directly map into any existing ATM service classes. (Note that the IETF Integrated Services specification already maps directly into ATM service classes since it assumes that the traffic can be specified.)
In the current ATM specification, there is no way of distinguishing data traffic priority within the UBR traffic class. In order to provide this support, the present invention pertains to a UBRw traffic class within UBR. It enables both IEEE 802.1p/Q and IETF Differentiated Services to map directly into the ATM UBR service class. Without the UBRw traffic class, ATM's growth in the Internet and enterprise network will be limited.
Some examples of such distinguished data traffic include:                A set of network end-points with better than UBR traffic QOS with unspecified UPC parameters.        A set of applications with better than UBR traffic QOS with unspecified UPC parameters.        An ISP could offer different grades of services to customers who require UBR traffic class.        Corporate VPNs can have different grades of services.        
Together with ATM's scalability and manageability, UBRw service would be very attractive to many ISPs. It would also be equally beneficial in enterprise ATM networks.
The present invention describes UBRw, a weighted traffic service within the UBR traffic class. UBRw allows for support of both IEEE 802.1p/Q and IETF Differentiated Services traffic classes. In addition, it eases the problem of specifying UPC for services without well-known traffic characteristics but with relative priority requirements.